Drying apparatus



Oct. 14, 1930.

H. HAAS DRYING APPARATUS Filed Nov.

2 Sheets-Sheet 1 l n a I I Inventor, Hermann fleas by HLWK MM A1 in Patent ed Oct. 14, l3ll UNITED STATES HERE-ANN HMS, OF LENNEP, GERMANY DRYING APPARATUS Application fledliovember 81, 1928. Serial No. 320,857.

" This invention relates to drying ap aratus of the type comprising an endless and conveyer on which the material to be dried is deposited and by which said material is carried through the drying chamber.

Whendrying material, such as loose textile fibres, ina drying apparatuspf this type, it is desirable that as largea quantity as possible of the material to be dried should be permeated by as large a quantity of air as possible in order to acilitate the drying operation. It iscommon practice to circulate the air through the dryin chamber and thus through the material to dried, by means of blowers and order that the blowers may move large quantities-of air it is customary to use low-pressure blowers capable of handling a large quantity of .air. If, however,--'

too great a thickness of material to be dried is placed on the endless conveyer the move ment of the air through the material will be choked to such an extent that the drying operation will not be accom lished efiiciently. On the other hand, if hig -pressure blowers are used instead of lowressure blowers there will be developed su cient air pressure to cause the air to circulate through the increased amount of material on the conveyor belt but as a high-pressure blower delivers considerably less air than a low-pressure blower the amount of air which is moved by the high-pressure bolwersimay not be sufficient to cause 'eficient drying. According to the present invention I problowers of one group being low-pressure and the blowers of the. other group being high-pressure 'blowerswhichd'eliver a relatively small quantity'of airfat high-pressure, the high p'ressure blowers being so disposed as to act on and loosenu the material on the drying belt. With this arrangement the high-pressure blowers serve to loosen up the increased amount of material which is placed on the belt. while the low-pressure blowers serve to move the large quantity of air which is necessary for eflicient drying.

In order to give! an understanding of the invention I have illustrated in the drawings pose to employ two groups of blowers, thebelt by another attendant. blowers which move large quantities of air a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claim.

Fig. 1 is a side view of a drying apparatus embodying my invention with a part broken out;

F i 2 is a cross section on substantially the line 22, Fig. 1;

Fig. 3 is a'plan view with a part broken 011 Fig. 4 is a cross section on the line 4-4, Fig. 1.

In the drawings 1 indicates generally. a drying chamber which is herein shown as divided into separate sections 2, 3 and 4.

-There may be any number of these sections in the casing depending on the manner in which the invention is used.

The material 18 to be dried is carried through the. drying chamber by an endless belt conveyer 5 which passes around direction pulleys 6 and 7, one of which is positively driven. These direction pulleys 6 and 7 are placed outside of the drying chamber 1 and the latter is formed in one end wall with an inletopening 8 through which the material to be dried passes and at the other end with a discharge opening 9 through which the dried material 1s delivered.

The conveyer 5 travels through the chamber from one end to the other and the material to be dried is placed on the portion 10 of said belt by an attendant. The dried material is removed from the portion 11 of the The drying is done by means of a drying current of air which is circulated through the drying chambers. The dr ing apparatus is formed with circulating passages 12 outside of the dr ing chamber, there being such a passage on each side of each of the sections 2, 3 and 4. Each circulating passage 12 communicates with the lower end of the drying chamber through an inlet' opening 13 and with theupper end of the drying chamber through an outlet or discharge opening 14.

Each discharge opening 14 has associated with it a low-pressure large volume air-forcing device 15 in the form ofa blower, the 10 blowers on opposite sides of each casing being mounted on the same shaft 16 which is driven through a suitable pulley 17 These blowers areconstructed and operated so as to suck or draw air from the drying chamber out through the discharge opening 14 and force air downwardly throughthe circulating passage 12 and back into the drying chamber through the inlet opening 13. Each inlet openin" 13 is situated below the upper run 'of the conveyer belt 5 so that the air which is deliveredto the chamber is delivered beneath the upper run of said conveyer. This conveyer is perforated so that the air can freely pass therethrough and thus pass upwardly through the material 18 on the conveyer.

Suitable heating means are employed in the passages 12 for heating the air before it is delivered through the inlet openings 13. Such heaters are indicated generally at 19 and may be of any suitable construction.

In addition to the low-pressure large volume blowers 15 I also employ one or more high-pressure small volume blowers which are situated to deliver air in small quantities but under high pressure directly underneath the upper run of the conveyer belt near the inlet opening. This high pressure air serves to loosen up the material 18 on the conveyer belt sothat the large quantity of-low.

pressure air which is moved by the blowers 15 can freely pass therethrough'and thus accomplish the drying operation.

In the present embodiment of my invention I have shown four high-pressure blowers which are indicated at 20 and 21 respectively. These high-pressure blowers are arranged with their discharge openings 22 situated directly underneath the upper run of the conveyer 5 and close to the inlet opening 8. The inlet 23 of eachof the blowers 20 communicates with an extension 24 of one of the circuof the belt is carried into the drying chamber through the opening 8 it is subjected to the action of the high-pressure blowers 20, 21. These serve to loosen up the material so that air can freely pass therethrough and hence the low-pressure air which is moved in large uantities by-the blowers 1'5 can freely pass t rough the material as it is carried along from one section to the other thereb greatly facilitating the drying operation. ince the current of ,air established by the large-volume low-pressure blowers is upwardly through the drying chamber the passage of said air upwardly through the loosened ma terial tends to maintain the material in its loosened condition thus facilitating the drying. With this invention, therefore, it is possible to increase the amount of material which is placed on the conveyer and thereby increase the amount of material which is dried in a given sect1on The high-pressure small-volume blowers.

20, 21 serve alsoanother purpose besides that of loosening up the material on the conveyer belt, that is, they create an air balanceat a the inlet opening 8 which tends to prevent the entrance of cold air at this point.

The action of the low-pressure large-volume blowers 15 operating in the section 2 tends normally to keep a reduced air pressure above the conveyer belt, a natural result of which would be to draw cold air in through the inlet 8. The high-pressure small-volume blowers, however, tend to compensate for this low pressure and to build up a pressure within the section 2 which will be suflicient to prevent the cold air from entering the inlet. It will be understood, of course, that the inlet opening 8 to the drying chamber and the delivery opening 9 will be of a proper size to accommodate the material to be dried.

I claim: 1 i

In a drying apparatus, the combination with a drying chamber, of an endless perforated conveyer extending through said chamher and adapted to carry therethrough the material to be dried, circulating passages at the sides of the drying chamber which communicate therewith both above and below the upper run of the conveyer, air-heating means in the circulating passages, low-pressure large-volume blowers arranged to move relatively large quantities of air from the up-,

per part of the drying'chamber into the cir- V culating passages downwardly through said passages into the lower portion of the drying chamber and then upwardly therethrough and through the material on the conveyer, and high-pressure small-volume blowers having their discharge ports situated directly beneath the upper run-of the conveyer adjacent the inlet end of the chamber, the inlet of each blower being arranged adjacent the communicating opening between the circulating passages and the lower portion -of the drying chamber, said blowers discharging the heated air against the under side of the upper run of the conveyer, thereby toloosen the material on the conveyer and the upward current created by the large-volume low-pressure blowers tending to retain the material in its loosened condition.

In testimony whereof, I have signed my name to this specification.

HER-MANN HAAS; 

